Geometric design of pyramidal antenna arrays for hemispherical scan coverage

An approach is presented for optimizing the geometry of pyramidal antenna arrays, given a full azimuth and a full or limited elevation scan requirement. It involves choosing the best face elevation and number of faces of the pyramid, which minimize the maximum scan angle while maximizing the geometric directivity. The analysis shows that the 4-face pyramid is the best choice. The derivation assumes that the distance to the antenna is infinite (the true far-field case). However, when finite distances are considered, the maximum scan angle increases only slightly at the minimum far-field distance used for low sidelobe pattern measurement. Index Terms--Geometric directivity, hemispherical scan coverage, maximum scan angle, multibeam antennas, pyramidal antenna arrays.